drivers/staging/lustre: Clean up another C warnining: set but not used

drivers/staging/lustre/lustre/fid/../include/lustre_cfg.h: In function 'lustre_cfg_free':
drivers/staging/lustre/lustre/fid/../include/lustre_cfg.h:253:6: warning: variable 'len' set but not used [-Wunused-but-set-variable]
  int len;

Yep, we're just gonna call kfree, no need to calculate len. Bye-bye.
Signed-off-by: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/include/lustre_cfg.h

@@ -252,10 +252,6 @@ static inline struct lustre_cfg *lustre_cfg_new(int cmd,
 
 static inline void lustre_cfg_free(struct lustre_cfg *lcfg)
 {
-	int len;
-
-	len = lustre_cfg_len(lcfg->lcfg_bufcount, lcfg->lcfg_buflens);
-
 	kfree(lcfg);
 	return;
 }